By virtue of the progress in information communication networks and the like such as the Internet in these few years, each user can now easily access network information through individual-oriented terminals employing a cellular phone or the like.
In such information communication, information is transmitted through digital signals. It is now possible to obtain copied music and video information transmitted via the aforementioned information communication network without degradation in the audio quality and picture quality of the copy information, even in the case where the copy operation is performed by an individual user.
Thus, there is a possibility of the copyright of the copyright owner being significantly infringed unless some appropriate measures to protect copyrights are taken when any created work subject to copyright protection such as music and image information is to be transmitted on the information communication network.
However, if copyright protection is given top priority so that distribution of copyrighted data through the disseminating digital information communication network is suppressed, the copyright owner who can essentially collect a predetermined copyright royalty for copies of a copyrighted work will also incur some disbenefit.
Consider the case of a recording medium recorded with digital information instead of the above-described distribution through a digital information communication network. As to the commercially-available CDs (Compact Disks) recorded with music information, copying music information from a CD to a magneto optical disk (MD) can be carried out basically arbitrarily as long as the copied music is used only for individual usage. Although indirectly, the individual user conducting digital recording and the like pays as a compensation a predetermined amount out of the cost of the digital recording equipment per se or the medium such as the MD to the copyright owner.
Based on the fact that the resultant music information constituted by digital signals, when copied from a CD to a MD, corresponds to digital information with almost no degradation through the copy operation, copying music data from one MD to another MD as digital information is disabled due to configuration constraints on the apparatus for the purpose of protecting copyright owners.
At the current stage, one can copy arbitrarily from a CD which is a digital recording medium to a MD, but not from a recordable MD to another MD.
In view of the foregoing, sufficient measures must be taken in distributing music and image information to the public through the digital information communication network for the purpose of copyright protection since distribution per se is an act subject to restriction based on the copyright owner's right of transmission to the public.
In this case, it is necessary to prevent any unauthorized user from receiving copyrighted data transmitted to the public through an information communication network, as well as preventing any copyrighted work, once received by an authorized user, to be further copied without permission.